Alcohol hits harder after weight loss surgery

NEW YORK (Reuters Health) - Weight loss surgery may turn people into light-weights in more than one sense, according to a new study that shows a glass of red wine hits much harder after the procedure than it used to.

That could affect patients' driving skills, and researchers say they should be extra careful about drinking after they've had surgery.

"You drink alcohol, your blood alcohol level is going to be higher than you think. Watch out," said Dr. Bruce Wolfe, the president of the American Society for Metabolic and Bariatric Surgery, who was not involved in the study.

"It's a precaution that should be passed along to virtually all the people who have gastric bypass," Wolfe told Reuters Health.

In 2009, more than 220,000 Americans had some type of weight loss surgery, at a price of about $20,000 per patient, according to the American Society for Metabolic and Bariatric Surgery.

Gastric bypass surgery reduces the stomach to a small pouch and bypasses part of the small intestine, so less food will be absorbed when it passes through the gut. The study did not look at other forms of weight loss surgery.

The researchers compared the effects of a glass of wine, guzzled in one minute, in 19 patients before surgery and three and six months later.

Using a breathalyzer test, the team measured patients' peak breath alcohol level, which is an indication of how much alcohol has been absorbed into a person's system.

On average, the peak level after a glass of wine was 0.024 percent before surgery. Six months later, it was 0.088 percent, which is higher than the legal driving limit of 0.08 percent.

"One glass of wine made people legally intoxicated," said Dr. John Morton, the director of bariatric surgery at Stanford University and the lead researcher on the study.

It also took 88 minutes for people's alcohol levels to return to zero after the surgery, compared to 49 minutes before the surgery.

Morton told Reuters Health that the changes are likely due to the stomach no longer being available to help process the alcohol. The weight loss itself did not account for the changes in breath alcohol or tipsiness, according to the researchers.

After the surgery, all of the patients in the study reported that they felt some effects of the wine, such as dizziness, warmth, or double vision. Before the surgery, eight out of 10 patients felt some effects.

"I think these issues with alcohol after surgery are still relatively rare," because people who have weight loss surgery make an effort to avoid the empty calories in alcohol, Morton said.

In fact, the people in this study did tend to drink less after surgery, but Morton said that was unlikely to have an impact on the way their bodies break down alcohol.

Morton's study was published last month in the Journal of the American College of Surgeons and was funded by Medical Research Grants from Stanford.

He said the elevated effect of alcohol after surgery should not discourage people from getting gastric bypass if it's right for them.

"I always tell people, you're not going to drink and drive before surgery, don't do it after, either," Morton said.